Merck Manual

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Denise Millstine

, MD, Mayo Clinic

Reviewed/Revised Dec 2023

Homeopathy, which was developed in Germany in the late 1700s, is a medical system based on the principle that like cures like (thus the name homeo [Greek for “like”] and patho [Greek for “disease”]). In other words, a substance that in large doses causes illness is believed to cure the same illness if given in very small doses. This tiny dose is thought to stimulate the body’s healing mechanisms. (See also Overview of Integrative, Complementary, and Alternative Medicine Overview of Integrative, Complementary, and Alternative Medicine Integrative medicine and health (IMH) and complementary and alternative medicine (CAM) include a variety of healing approaches and therapies that historically have not been included in conventional... read more .)

Homeopathy aims to restore the flow of the body's innate life force. Treatments are based on a person’s unique characteristics, including lifestyle as well as symptoms and general health.

The remedies used in homeopathy are derived from naturally occurring substances, such as plant and animal extracts and minerals. These substances are thought to stimulate the body’s innate capacity to heal. Remedies are prepared by diluting these substances over and over. Many homeopathic remedies are diluted so much that none of the original substance is detectable. However, some homeopathic remedies contain other ingredients that can affect the body.

Scientific explanation for how ultradiluted remedies used in homeopathy cure illness is lacking. There is no accepted physical or chemical basis for the homeopathic principle that "like cures like."

Did You Know...

  • Some homeopathic remedies contain no detectable amount of the active ingredient.

In the United States, homeopathic remedies are classified by the U.S. Food and Drug Administration (FDA) as over-the-counter or prescription medications, but the FDA exempts these remedies from several requirements that other medications must meet. For example, the identity and strength of each active ingredient do not have to be tested by a laboratory before the remedy is sold. Also, manufacturers of homeopathic products are not required to provide evidence that the products are effective. Homeopathic remedies may contain alcohol, which is often used to dilute drugs. There are currently no limits on the amount of alcohol that these remedies can contain.

The label is required to have the following:

  • The word “homeopathic”

  • The manufacturer’s name

  • Mention of at least one way the drug can be used

  • Instructions for safe use

  • The active ingredient and amount of dilution (unless specifically exempted)

Some homeopathic drugs are available by prescription only.

Medicinal Uses of Homeopathy

Homeopathy has been used to treat various disorders, such as allergies, respiratory symptoms, digestive problems, musculoskeletal pain, and vertigo. Homeopathic remedies for many of these disorders have been studied. Evidence suggests that homeopathic remedies are not effective.

Possible Side Effects of Homeopathy

Most people tolerate homeopathic remedies well, and taking these remedies has few risks. However, side effects, such as allergic reactions and toxic reactions, can occur.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  • National Center for Complementary and Integrative Health (NCCIH): Homeopathy

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